235 lines
9.9 KiB
C
235 lines
9.9 KiB
C
/**************************************************************************/
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/* */
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/* Copyright (c) Microsoft Corporation. All rights reserved. */
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/* */
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/* This software is licensed under the Microsoft Software License */
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/* Terms for Microsoft Azure RTOS. Full text of the license can be */
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/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
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/* and in the root directory of this software. */
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/* */
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/**************************************************************************/
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/**************************************************************************/
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/**************************************************************************/
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/** */
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/** ThreadX Component */
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/** */
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/** Semaphore */
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/** */
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/**************************************************************************/
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/**************************************************************************/
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#define TX_SOURCE_CODE
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/* Include necessary system files. */
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#include "tx_api.h"
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#include "tx_trace.h"
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#include "tx_thread.h"
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#include "tx_semaphore.h"
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/**************************************************************************/
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/* */
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/* FUNCTION RELEASE */
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/* */
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/* _tx_semaphore_get PORTABLE C */
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/* 6.1 */
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/* AUTHOR */
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/* */
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/* William E. Lamie, Microsoft Corporation */
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/* */
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/* DESCRIPTION */
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/* */
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/* This function gets an instance from the specified counting */
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/* semaphore. */
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/* */
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/* INPUT */
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/* */
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/* semaphore_ptr Pointer to semaphore control block*/
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/* wait_option Suspension option */
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/* */
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/* OUTPUT */
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/* */
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/* status Completion status */
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/* */
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/* CALLS */
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/* */
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/* _tx_thread_system_suspend Suspend thread service */
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/* _tx_thread_system_ni_suspend Non-interruptable suspend thread */
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/* */
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/* CALLED BY */
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/* */
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/* Application Code */
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/* */
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/* RELEASE HISTORY */
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/* */
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/* DATE NAME DESCRIPTION */
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/* */
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/* 05-19-2020 William E. Lamie Initial Version 6.0 */
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/* 09-30-2020 Yuxin Zhou Modified comment(s), */
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/* resulting in version 6.1 */
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/* */
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/**************************************************************************/
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UINT _tx_semaphore_get(TX_SEMAPHORE *semaphore_ptr, ULONG wait_option)
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{
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TX_INTERRUPT_SAVE_AREA
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TX_THREAD *thread_ptr;
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TX_THREAD *next_thread;
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TX_THREAD *previous_thread;
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UINT status;
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/* Default the status to TX_SUCCESS. */
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status = TX_SUCCESS;
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/* Disable interrupts to get an instance from the semaphore. */
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TX_DISABLE
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#ifdef TX_SEMAPHORE_ENABLE_PERFORMANCE_INFO
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/* Increment the total semaphore get counter. */
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_tx_semaphore_performance_get_count++;
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/* Increment the number of attempts to get this semaphore. */
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semaphore_ptr -> tx_semaphore_performance_get_count++;
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#endif
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/* If trace is enabled, insert this event into the trace buffer. */
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TX_TRACE_IN_LINE_INSERT(TX_TRACE_SEMAPHORE_GET, semaphore_ptr, wait_option, semaphore_ptr -> tx_semaphore_count, TX_POINTER_TO_ULONG_CONVERT(&thread_ptr), TX_TRACE_SEMAPHORE_EVENTS)
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/* Log this kernel call. */
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TX_EL_SEMAPHORE_GET_INSERT
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/* Determine if there is an instance of the semaphore. */
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if (semaphore_ptr -> tx_semaphore_count != ((ULONG) 0))
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{
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/* Decrement the semaphore count. */
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semaphore_ptr -> tx_semaphore_count--;
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/* Restore interrupts. */
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TX_RESTORE
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}
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/* Determine if the request specifies suspension. */
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else if (wait_option != TX_NO_WAIT)
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{
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/* Determine if the preempt disable flag is non-zero. */
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if (_tx_thread_preempt_disable != ((UINT) 0))
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{
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/* Restore interrupts. */
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TX_RESTORE
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/* Suspension is not allowed if the preempt disable flag is non-zero at this point - return error completion. */
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status = TX_NO_INSTANCE;
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}
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else
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{
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/* Prepare for suspension of this thread. */
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#ifdef TX_SEMAPHORE_ENABLE_PERFORMANCE_INFO
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/* Increment the total semaphore suspensions counter. */
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_tx_semaphore_performance_suspension_count++;
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/* Increment the number of suspensions on this semaphore. */
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semaphore_ptr -> tx_semaphore_performance_suspension_count++;
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#endif
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/* Pickup thread pointer. */
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TX_THREAD_GET_CURRENT(thread_ptr)
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/* Setup cleanup routine pointer. */
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thread_ptr -> tx_thread_suspend_cleanup = &(_tx_semaphore_cleanup);
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/* Setup cleanup information, i.e. this semaphore control
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block. */
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thread_ptr -> tx_thread_suspend_control_block = (VOID *) semaphore_ptr;
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#ifndef TX_NOT_INTERRUPTABLE
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/* Increment the suspension sequence number, which is used to identify
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this suspension event. */
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thread_ptr -> tx_thread_suspension_sequence++;
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#endif
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/* Setup suspension list. */
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if (semaphore_ptr -> tx_semaphore_suspended_count == TX_NO_SUSPENSIONS)
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{
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/* No other threads are suspended. Setup the head pointer and
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just setup this threads pointers to itself. */
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semaphore_ptr -> tx_semaphore_suspension_list = thread_ptr;
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thread_ptr -> tx_thread_suspended_next = thread_ptr;
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thread_ptr -> tx_thread_suspended_previous = thread_ptr;
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}
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else
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{
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/* This list is not NULL, add current thread to the end. */
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next_thread = semaphore_ptr -> tx_semaphore_suspension_list;
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thread_ptr -> tx_thread_suspended_next = next_thread;
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previous_thread = next_thread -> tx_thread_suspended_previous;
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thread_ptr -> tx_thread_suspended_previous = previous_thread;
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previous_thread -> tx_thread_suspended_next = thread_ptr;
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next_thread -> tx_thread_suspended_previous = thread_ptr;
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}
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/* Increment the number of suspensions. */
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semaphore_ptr -> tx_semaphore_suspended_count++;
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/* Set the state to suspended. */
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thread_ptr -> tx_thread_state = TX_SEMAPHORE_SUSP;
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#ifdef TX_NOT_INTERRUPTABLE
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/* Call actual non-interruptable thread suspension routine. */
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_tx_thread_system_ni_suspend(thread_ptr, wait_option);
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/* Restore interrupts. */
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TX_RESTORE
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#else
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/* Set the suspending flag. */
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thread_ptr -> tx_thread_suspending = TX_TRUE;
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/* Setup the timeout period. */
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thread_ptr -> tx_thread_timer.tx_timer_internal_remaining_ticks = wait_option;
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/* Temporarily disable preemption. */
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_tx_thread_preempt_disable++;
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/* Restore interrupts. */
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TX_RESTORE
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/* Call actual thread suspension routine. */
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_tx_thread_system_suspend(thread_ptr);
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#endif
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/* Return the completion status. */
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status = thread_ptr -> tx_thread_suspend_status;
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}
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}
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else
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{
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/* Restore interrupts. */
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TX_RESTORE
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/* Immediate return, return error completion. */
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status = TX_NO_INSTANCE;
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}
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/* Return completion status. */
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return(status);
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}
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